$("#fullbtn").click(function () {
  if ($(this).hasClass("full")) {
    //取消全屏
    $(this).removeClass("full");
    var el = document;
    var cfs =
      el.cancelFullScreen ||
      el.webkitCancelFullScreen ||
      el.mozCancelFullScreen ||
      el.exitFullScreen;
    //typeof cfs != "undefined" && cfs
    if (cfs) {
      cfs.call(el);
    } else if (typeof window.ActiveXObject !== "undefined") {
      //for IE，这里和fullScreen相同，模拟按下F11键退出全屏
      var wscript = new ActiveXObject("WScript.Shell");
      if (wscript != null) {
        wscript.SendKeys("{F11}");
      }
    }
  } else {
    //全屏
    $(this).addClass("full");
    var el = document.documentElement;
    var rfs =
      el.requestFullScreen ||
      el.webkitRequestFullScreen ||
      el.mozRequestFullScreen ||
      el.msRequestFullScreen;
    //typeof rfs != "undefined" && rfs
    if (rfs) {
      rfs.call(el);
    } else if (typeof window.ActiveXObject !== "undefined") {
      //for IE，这里其实就是模拟了按下键盘的F11，使浏览器全屏
      var wscript = new ActiveXObject("WScript.Shell");
      if (wscript != null) {
        wscript.SendKeys("{F11}");
      }
    }
  }
});
